docs: Fix relative URL settings in config.toml.
docs: Fix relative URL settings in config.toml.

This sets relativeURLs to false (the default value). If it's set to true,
then the URLs generated by Hugo are incorrect.

e.g., in the HTML the incorrect URL is created starting with "./".

    <link
      href='./docs/badger/css/theme.css?ed88a5fdbf06b9737b9afdf41f9e2902'
      rel="stylesheet"
      />

With this change, the correct URL is created starting with "/".

    <link
      href='/docs/badger/css/theme.css?ed88a5fdbf06b9737b9afdf41f9e2902'
      rel="stylesheet"
      />

dgraph-io/badger,dgraph-io/badger